Improvement in grates for steam-boiler furnaces



L JT@ M ff. f .Paf/Wmme wif.

.:' I heating capacity '/'UNITED STATES;

PATENT OFFICE, l

GEORGE L. SMITH, oEBR'ooKLrN, NEW Yoan.

' "IMPBOVEMENE IN'GRATE'S- .apaisement-arming@ sfi-ieaeisrsteet :am

" Fig. 2 isjan end vievy of the same, as seen at l the furnace-door; andFig, 3 is a plan View ot' one of the 'truss-supporters.

, The objects of'myinvention are, first, tQ `lessen thenwear and destruction of grate's einployedin steam-boiler furnaces and other po- Sitiesnhere great beanie esaltanti; Seoud;

`to eect a saving of fuel by increasingl the o't1 such furnaces with a given amount of fuel.

The diiculties, inconvcniencesglmd expense attending the wearand destruction ofthe gratebars ot boilerand otheii" Ifurnaces are 'Y Well 4known'to all practical engineers, and'various modes have been tried to overcome these objections, 'but with little ties rnentiond is due to the 'unequal expansion `due to the grate-surface,

on its upper part, while the uuderpart thereof y iskeptcomparatively copl 'by the passing air required to supportcombustion. The eft'ectis .that the top surface of the grates, being expanded by heat, must either crown up, Warp sidewise, or do both. Experience has proved that the gratas thus bent ut of shape never resume their original form when cooled, andare by eachpsubsequent heating impaired in qua1- ity, so that they soon become valneless for-the purposel intended."` .To overcome these dif f- `v-cultics grate-bars of various shapes and forms fg'have u beem tried, including, among others', irregular fsllialpes, serpentine lock-bars, and bars of'greatiiveght of metal with deep trusses cast thifrlinder side; but with all these, as ,vth/thietcoirtnnon form of gratebanitisfound Vthat'"notfimiyfl does the difficulty above named increase Withv the increased weight of metal a full and exact descrip,

Wsuccess. It"is, ap advmitted fact that the,inain cause of the ditlculbeing intensely heatedfoR STEAM-Bones FURNAoEs.

used in the gra tebar, but that .air-openings-between tbe bars are decreased in some and increased, of course', in others, so that a sufficient supply of air to support combustibn is not afforded in the `one case, while 'in the other case the expanded openings cause a serious waste ot' fuel. When the gra-tes are expanded so that the air space or opening, as

above stated. is decreased in capacity, the-result uniformly is that the face-of the bar is burned Aby the intense heat, causing theelinker from lthe coal toamalgamate with it, effectually checking the passage of'air between the grates so situated,cansing theirrapiddestrnc- All the diliculties and objections above named I claim to have overcome by my ini-V provemenn the nature of Whichconsists in so constructing agrate for furnaces as to, ins ure greaterstren offmetahwhich I eicct by constructing my entire grate-surface ot a series of small shallow sections, A', of such size and forni` (beingabont theproportions shown in the drawings) as that eachwhen heated will expand alike inv all its` parts. .These sections are supported by a seris of truss-bars, 15 and so placed that each and every section-Aris supported by and balanced upon' t\vo.ot" the supports, or truss-bars B-that is, that the part of every section which overhangs the two `truss-bars upon which itis placed and 'supported shall equal the Weight of 'the part of the section between the'two trussbars,so that `the section cannot sag down or break or alter its shape, as would be, and is, the case with 'ordinary grate-bars and sectional grates of otherlform supported at their ends, when highly heated.

I construct the trusses or supports B insuch manner, on the top surface thereof,that the heat of the grate-sections is not transmitted to them, thus insuring, with little Weight ot metal, a sufficient strength of truss to support l the sections and the Weight of fuel upon th'em, .and also an unobstructed passage through the openings of the sections for the air upward y and the ashesI and clinkers downward. These trusses B 'are placed upon the ordinarygratebar-bearer, C; as shown it should be understoodjthat the truss or bag- Y the spaces forv gth and durabilltywith less'treight" Y in Figs. l and 2; andl 2 sansabrace supports are constructed separate from both. the grated sections and the bearers. It is by this that one of thc'.most important results is attained. In other words, although the trusses rest. upon the bearers, ,and the grated sections upon trusses, each of these is free from the others, so far as positive bind bc- Vtween oneV another is concerned. Therefore any .one of the three destructive parts making upl the grate-to wit, grated sections, truss-supports, and bearers-can accolnniodateit'self to the expansion and contraction or to any ch ange in the relation ot' any portion ot' the bearings'urface ot'- one. piece with any portion of-the bearing-surface ofano? h er piece occurringi'rom any cause. By having the grated surface made up throughout its area of small narrow Lsections which nre subdivided by transverse divisions any part'ot' the grated surface may be readily removed, and that, too, without disturbing the bars or trusses, as they (the bars) are independent structures from the grated.

surface. This facilityof removal of any section renders the'repair ofthe grate a very simple and cheap operation, as a new section,

or any number of sections,may be substituted in a short time for thedestroyed sections.

I will here state thatl ,my invention dii'ers from all grates heretofore'use'd, rst, in divid- .in'ga grate formed of one large piece, or a4 grate formed of two 'or four pieces, into a se- 'ries ot' small sections, uponthe systemy described and represente-d; second, in supporting each of these small sections upon discon- The advantages of '1n-y improvement over all othergrates in use I claim to be, first, economy in cost by combining great strength with lessened weigst; second, economy o'f fuel with increased heat; 'third, security against the possibility of sagging or breaking down of the grate-sections; i'ourth,great`er. durability ot' the grate.

Having thus and advantages of my improvement, what I claim as my invention, and desire to secure by4 Letters Paten t, is v 1. Trusses or supports for agrated surface, made free from the grated surface and from the transverse bearers, substantially as and for the purposes set forth. g 1

2. So arranging the sections and the trusses .or supports of a sectional grate that each section will b e supported and balanced substantiay in the manner described;

eno. L( sMirn.,v

y Witnesses:

ROB'LF. SMITH,

. D. H. MoDoNNELL.

described the object, nature, A 

